1. Field of the Invention
This invention is directed to pumps, in general, and, more particularly, to hydraulically controlled pumps which are used to pump coarse, viscous materials such as concrete.
2. Prior Art
There are many types of pumping machines which are known in the art. These pumps vary in function from those which are used to pump fluids such as gaseous materials, through pumps for liquids, to those types of pumps which are used to pump highly viscous, particulate material. The known pumps can be used to pump other materials such as slurries, granular material or the like. One particular type of pump apparatus which is well known in the art is used to pump concrete from a mixer apparatus to a remote location of utilization. These pumps are frequently hydraulically powered so as to provide a sufficient force to move the relatively heavy concrete mixer. Many of the existing pumps use a ball valve to control the flow of concrete from the input source to the delivery line.
However, in many cases, a relatively dense or coarse concrete mixture is required for various applications. With this type of concrete, it is virtually impossible to use the existing ball valve in the pump. That is, the dense and/or coarse material tends to become congested in the ball valve. This effect causes the pump to become clogged and inoperative.
In the past, a gate or spade valve has been utilized but has been relatively ineffective because of leakage, excessive wear and other shortcomings. Thus, the existing gates have been relatively ineffective and undesirable. Therefore, a new and improved gate arrangement is highly desirable.